1. Field of the Invention
This invention relates generally to a flow sensor, and more particularly to a flow sensor for determining if a proper quantity of liquid is being delivered in a delivery system.
2. Description of the Prior Art
Constant volume pumps are universally used as the least expensive dispensing method for delivering small quantities of liquids to applications. Constant volume pumps consist of a flexible elastomer tube, a rotor and a small motor. When power is applied to the motor, it turns the rotor and collapses the tube, which squeezes liquid out of the tube and to the application. Constant volume pumps are capable of delivering very small volumes of liquid at constant flow rates. This allows for the pumps to be controlled by simple timers to deliver a pre-determined amount of liquid. Some problems that are associated with constant volume pumps include that the pump tube wears out over time and has to be replaced. Service personnel typically replace the tubes according to a maintenance schedule. In addition, as the pump tubes wear, the volume they pump may change, possibly to the point where they are no longer pumping the required volumes to the application. Still another problem is that when the dispensed liquid container goes empty, the pump will not give any indication to the customer to replace the liquid container.
The present invention addresses the problems associated with the prior art constant volume pumps and provides for a flow verification mechanism for use with such constant volume pumps, constant volume pumps or other type of pumps.